1. Field of the Invention
The present invention relates to portable frac trucks and, more specifically, to a customize filter baghouse for use in conjunction with portable frac trucks.
2. Description of the Related Art
Hydraulic fracturing is the term describing the method used to increase or restore the rate at oil, gas or water, can be produced from a well. Wells located in unconventional reservoirs such as shale rock or coal beds are particularly heavy users of hydraulic fracturing. This technique enables the production of natural gas and oil from rock formations deep below the earth's surface where there may not be sufficient porosity and permeability to allow natural gas and oil to flow from the rock into the well bore and be recovered. The low natural permeability of shale and coal make creating conductive fractures in the rock essential to the economic production of gas from shale reservoirs. The fracture provides a conductive path connecting a larger area of the reservoir to the well, thereby increasing the are a from which natural gas and liquids can be recovered from the targeted formation.
The general objective to hydraulic fracturing is the increased amount of exposure a well has to the surrounding formation, and providing a conductive channel through which injected water or produced natural gas or oil can flow easily to or from the well. A hydraulic fracture is formed by pumping the fracturing fluid into the well bore at a rate sufficient to increase the pressure downhole to a value in excess of the fracture gradient of the formation rock. The pressure causes the formation to crack, allowing the fracturing fluid to enter and extend the crack further into the formation. To keep this fracture open after the injection stops, a solid proppant is added to the fracture fluid. The proppant, which is commonly a sieved round sand, is carried into the fracture. This sand is chosen to be higher in permeability than the surrounding formation, and the propped hydraulic fracture then becomes a high permeability conduit through which the formation fluids can flow to the well.
The injected fluid mixture is approximately 99.5% water and sand.
Hydraulic fracturing equipment used in oil and natural gas fields usually consists of a slurry blender, one or more high pressure, high volume fracturing pumps and a monitoring unit. Associated equipment includes fracturing tanks, a chemical additive unit (used to accurately monitor chemical addition) low pressure pipes and gauges for flow rate, fluid density, and treating pressure.
Typically, hydraulic fractures are placed in cased wellbores and the reservoir zones to be fractured are accessed by perforating the casing at those locations. Thus, the equipment is usually truck mounted to be able to be moved from well to well for servicing. Frac Trucks, sometimes called soup trucks, kettle trucks, frac trucks, or sand trucks, are used to haul frac sand or cement for gas well casings. The truck mounted equipment accurately meters and conveys a dry powder or granular material to a blender in a substantially closed system in order to contain and control any adverse environmental effects.
In operation, the frac truck, once positioned at the well site to be serviced, includes a storage tank to hold the dry powder or granular material (sand), a hopper for mixing and dispensing the granular material, a conveyor which delivers the dry powder or granular material to the hopper from the storage tank. As the hoppers are filled with fractioning sand, air is displaces from the hoppers and is discharged into the atmosphere. This displaced air entrains powder or sand in the process, creating an airborne environmental hazard that, to date, has not been addressed.
Consequently, a need exists for a method of filtering or collecting any particulate material that is discharged through the vent opening when a vessel is being loaded.